The present invention relates generally to instruments for use in endoscopic or laparoscopic surgery and, more particularly, to a surgical handle having a controlled leak passage.
In laparoscopic surgical procedures, long and narrow instruments are used to perform surgery on tissues and vessels inside an insufflated abdomen through a small incision in the skin. Many laparoscopic instruments require actuation of jaws or other mechanisms on the instrument's distal end inside the abdomen.
For example, a surgical clip applier may be used for applying surgical clips to blood vessels, ducts or the like in laparoscopic or endoscopic procedures. In some cases, the clip applier may have a reusable handle and a disposable endoscopic portion. In such cases, the handle should be designed to permit its thorough cleaning between uses to insure proper mechanical operation and to prevent infection or the like, while the disposable endoscopic portion may be discarded after use.
In U.S. Pat. No. 5,100,420 to Green et al., the endoscopic portion has a long and relatively narrow tube for insertion into a body cavity through a trocar or a small incision. The endoscopic portion includes a pusher bar for advancing surgical clips one at a time to a pair of flexible opposing jaws that close the clips around a vessel or duct. The jaws are clamped together by a distally moving channel. The handle includes a lever for actuating the jaw closing channel and a longitudinally sliding member for actuating the clip advancing pusher bar to load another clip between the jaws. A gaseous seal is provided in the endoscopic portion to prevent communication of gases through the incision. The seal is accomplished by providing close tolerances for the internal moving parts. In a specific embodiment, the gaseous seal includes a seal block with an opening for the pusher bar and the jaw closing channel. The inner surface of the seal block is in close contiguity with the surfaces of the pusher bar and the channel. A layer of silicone grease may be employed to prevent gases from leaking between the surfaces.
Providing a seal by manufacturing parts to close tolerances requires additional time and effort during the manufacture and assembly operations and adds significantly to the cost of the endoscopic portion. In the case of a disposable endoscopic portion, cost is especially important since it is a single use item. In addition, using silicone grease adds to the cost of the item, as well as to its manufacture and assembly.
From the discussion above, it should be apparent that there is a need for a laparoscopic surgical instrument that does not require a seal, but that is still useful in laparoscopic and endoscopic procedures. Additionally, the reusable part of such an instrument should be designed to permit easy cleaning.